Holy balls! Did you watch the Home Run derby the other night? I didn't. But if I had, I would have wondered: How did they manage to show those cool balls' trails in real time?

The mechanism involves a complicated math algorithm that tracks and predicts the ball's trajectory in real time, only 400 milliseconds after being hit. To get the data needed for the calculation, ESPN uses a 2000Hz Doppler radar which follows the ball's speed, location and spin, given precise data of distance travelled, something that before took seconds or even minutes to calculate. After calculation, the path is shown overlaid on screen in real time, chasing the ball precisely.

The results are quite cool, even while they fail (again) at making baseball exciting to me. [Popular Science]